Final report for GNC20-294
Project Information
“Establishing Pullet Welfare Measurements and Guidelines for Growers and Managers on Commercial Poultry Farms” is geared toward pullet managers and producers in the North-Central region. This region contains a large proportion of egg production in the United States. Welfare measurements will first be trialed on commercial farms in Indiana and then expanded into the entire North-Central region. Information gained will be shared through a peer-reviewed, numbered extension article and accompanying videos. These videos will demonstrate skills described in the article. If our project is successful, pullet managers and producers will acquire and implement welfare measurements and skills to evaluate and adjust their management styles on a flock-by-flock basis. As a result, the pullets will have improved immune function, increased growth and production efficiencies, and decreased stress. We are currently trialing and validating measurements of stress and welfare in pullets on a research farm. This project will test these same measurements on commercial farms. This will identify any correlation or practicality issues between experimental and in-the-field testing and results. Our measurements will include physiological, immunological, and behavioral parameters. Together, these measurements will create a comprehensive image of a pullet’s adaptability to her environment. This project’s success will depend on feedback from the managers and growers using the information. A survey will be sent to all companies receiving the extension bulletin and videos to gain insight into their influence on management behavior. This information will help the principal investigator revise the document for future disseminations.
If our extension publication and training videos are successful, we expect to see pullet managers and growers acquire knowledge about possible welfare measurements and the skills required to implement them. After managers and growers become more comfortable with understanding welfare assessments and how to complete them, they can use these assessments as a means of evaluating their pullet management (optimal management styles will produce higher welfare scores on each of the parameters measured and are preferred over styles that produce lower scores). If more managers and growers adopt these welfare assessments, they will see improved and honed-in management strategies that they can adjust on a flock-by-flock basis. This will lead to improved immune function, increased growth and production efficiencies, and decreased stress to the birds. We will evaluate successful welfare assessment implementation through a follow-up survey for producers and managers. In the long term, researchers and farm staff will have collaborated with each other in order to generate practical on-farm guidelines for the welfare and management of pullets. This may drive formal welfare certifications for pullets which are important for egg label marketing. They may be adopted by UEP and Certified Humane© labels which have standards for adult hens but not pullets.
Research
In the last two years (2021-2022), data analysis from three research studies at the Purdue University poultry research facilities wrapped up. The results of these studies identified that bursal size and feather coverage may be useful measures of pullet welfare. A huge caveat to these studies is that many of the results pointed toward resilience or stress resistance during the pullet phase. Stress resistance during the pullet phase means that identifying measurements of welfare could be difficult. The pullets in all three research studies appeared to generally thrive despite the internal and external stressors applied. The next step was to test bursal size and feather coverage differences on commercial pullet facilities. However, highly pathogenic avian influenza (HPAI) prevented us from entering commercial facilities to collect data.
In order to meet one of our objectives to generate extension articles for producers (despite being able to complete our research as planned), we were able to test a new vaccine system and write up an article about our experience using the equipment. The extension bulletin also covers some vaccination basics.
A survey soliciting industry opinions of poultry welfare and potential stress and welfare markers on farm received IRB approval and was sent out to several industry organizations/publications. There were over 72 responses to this survey, 11 of the respondents were involved in daily bird care. The remaining respondents provided support for farmers.
Approximately 80% of survey respondents thought measuring welfare on farm is useful and approximately 90% of respondents use principles of animal welfare most or all of the time. The largest obstacles to measuring welfare on farm were not having enough financial, labor, or time resources to complete the task. If farmers or support staff are going to measure welfare on farm, an adequate amount of resources may be the largest limiting factor.
Respondents ranked several welfare measurements based on usefulness, feasibility, and cost-effectiveness (details describing these parameters are listed below). Vaccine titer, corticosterone, immune organ size, feather coverage, and shank length were ranked as the most useful measures of welfare while body weight uniformity, feed conversion ratio, foot condition, and body weight were ranked lower for usefulness. Immune organ size measurements and blood draws for corticosterone and vaccine titer evaluation were ranked as the most feasible welfare measurements. Feather coverage and shank length were ranked as the least feasible welfare measurements. Foot condition and production measurements had an intermediate level of feasibility. Feather coverage and blood collection were some of the least cost effective measures. Immune organ size and production measurements were considered some of the most cost effective measures.
When considered together, immune organ size was ranked highly for usefulness, feasibility, and cost effectiveness. This information, paired with the on-farm studies suggest that bursal measurements (an immune organ) may be a useful and feasible measure of welfare. Further study would be required to determine the accuracy of bursal size and how it may translate to differences in immunity before implementing this measurement in formal welfare assessments.
The following details were provided to survey respondents regarding the different measures of welfare:
- Blood draws to measure hormone levels and vaccine titers for immunity (20-30 minutes and $200-500 required)
- During stress, hormones are elevated and result in many changes in the birds growth, metabolism, and immunity
- During stress, birds have reduced immunity
- Size of immune organs (60-90 minutes and $20-150 required)
- During stress, the immune organs can decrease in size resulting in decreased immunity
- Feather coverage of the bird (20-60 minutes and labor only costs required)
- During stress, birds can have reduced feather coverage
- Length of the bird’s leg (shank length; 20-45 minutes and labor only costs required)
- During stress, birds’ growth can be reduced resulting in shorter legs
- Foot condition (20-30 minutes and labor only costs required)
- Is there a little or a lot of damage to the birds’ feet? During stress, foot condition can be impaired.
- Production measurements (30-45 minutes and labor only costs required) :
- Body weight uniformity
- How closely are all the birds matched in body weight? During stress, uniformity is decreased.
- Feed conversion ratio (FCR); how much a bird eats in relation to how much it gains in body weight
- During stress, FCR can worsen (be higher)
- Bird body weight
- During stress, body weights can decrease
- Body weight uniformity
Educational & Outreach Activities
Participation Summary:
The results of the pullet welfare research was presented at the Midwest Poultry Federation (2021), American Association of Avian Pathologists (2022), and the Poultry Science Association (2021 and 2022) annual meetings. A peer-reviewed, numbered, extension article is published on the Purdue University extension website (https://edustore.purdue.edu/item.asp?Item_Number=AS-690-W ). Two articles in Watt Poultry covered the results of our pullet welfare research (https://www.wattagnet.com/articles/44753-how-does-stocking-density-affect-pullet-welfare and https://www.wattagnet.com/articles/45815-pullets-seem-unaffected-by-stocking-density-feeder-space )
The survey results will be published as an extension article and in a scientific journal.
Project Outcomes
We were unable to achieve our outcome of testing potential markers of pullet stress and welfare on commercial pullet facilities due to the highly pathogenic avian influenza (HPAI) outbreak. However, the results of our survey identified industry viewpoints on poultry welfare and potential welfare measurements that can be done for poultry on farm. The survey identified trends in what respondents thought was useful, feasible, and cost-effective on farm. An understanding of these principles will help narrow down which parameters should be used on commercial pullet facilities in the future. By increasing industry knowledge about viewpoints on poultry welfare, producers will have a better idea of what's available to measure welfare and will have a better idea of how much their ideas align with others in the industry.
The results of the welfare research identified that pullets thrive at both high and low stocking densities as well as at normal and reduced feeder space. This indicates that the current industry practices are sustainable and appropriate for bird welfare. The results of the research indicate that pullets could thrive at even tighter stocking densities than are currently used in industry without their welfare suffering. Increasing stocking densities reduces resources used to produce the same amount of bird/eggs.
Results of the survey identified that ~80% of respondents thought measuring welfare on farm is useful and ~90% of respondents use principles of animal welfare most or all of the time. The largest deterrents to measuring welfare on farm were not having enough financial, labor, or time resources to complete the task. In order to maintain sustainable agriculture practices that also maintain good bird welfare, the industry will have to ensure that appropriate resources are provided. The measurement of the bursa of Fabricius, an immune organ, shows promise as a useful tool for welfare measurement on farm. Research studies identified bursal size as a possible marker of stress and welfare and survey respondents ranked immune organ size measurements highly for cost-effectiveness, feasibility, and usefulness.